mirror of
https://github.com/StackExchange/dnscontrol.git
synced 2025-01-10 17:38:13 +08:00
108 lines
3.3 KiB
Go
108 lines
3.3 KiB
Go
package normalize
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import (
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"fmt"
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"strconv"
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"strings"
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"github.com/StackExchange/dnscontrol/v3/models"
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"github.com/StackExchange/dnscontrol/v3/pkg/spflib"
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)
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// hasSpfRecords returns true if this record requests SPF unrolling.
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func flattenSPFs(cfg *models.DNSConfig) []error {
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var cache spflib.CachingResolver
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var errs []error
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var err error
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for _, domain := range cfg.Domains {
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txtRecords := domain.Records.GetByType("TXT")
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// flatten all spf records that have the "flatten" metadata
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for _, txt := range txtRecords {
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var rec *spflib.SPFRecord
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txtTarget := strings.Join(txt.TxtStrings, "")
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if txt.Metadata["flatten"] != "" || txt.Metadata["split"] != "" {
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if cache == nil {
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cache, err = spflib.NewCache("spfcache.json")
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if err != nil {
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return []error{err}
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}
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}
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rec, err = spflib.Parse(txtTarget, cache)
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if err != nil {
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errs = append(errs, err)
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continue
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}
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}
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if flatten, ok := txt.Metadata["flatten"]; ok && strings.HasPrefix(txtTarget, "v=spf1") {
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rec = rec.Flatten(flatten)
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err = txt.SetTargetTXT(rec.TXT())
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if err != nil {
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errs = append(errs, err)
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continue
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}
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}
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// now split if needed
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if split, ok := txt.Metadata["split"]; ok {
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overhead1 := 0
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// overhead1: The first segment of the SPF record
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// needs to be shorter than the others due to the overhead of
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// other (non-SPF) txt records. If there are (for example) 50
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// bytes of txt records also on this domain record, setting
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// overhead1=50 reduces the maxLen by 50. It only affects the
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// first part of the split.
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if oh, ok := txt.Metadata["overhead1"]; ok {
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i, err := strconv.Atoi(oh)
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if err != nil {
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errs = append(errs, Warning{fmt.Errorf("split overhead1 %q is not an int", oh)})
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}
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overhead1 = i
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}
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// Default txtMaxSize will not result in multiple TXT strings
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txtMaxSize := 255
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if oh, ok := txt.Metadata["txtMaxSize"]; ok {
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i, err := strconv.Atoi(oh)
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if err != nil {
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errs = append(errs, Warning{fmt.Errorf("split txtMaxSize %q is not an int", oh)})
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}
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txtMaxSize = i
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}
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if !strings.Contains(split, "%d") {
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errs = append(errs, Warning{fmt.Errorf("split format `%s` in `%s` is not proper format (missing %%d)", split, txt.GetLabelFQDN())})
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continue
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}
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recs := rec.TXTSplit(split+"."+domain.Name, overhead1, txtMaxSize)
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for k, v := range recs {
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if k == "@" {
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txt.SetTargetTXTs(v)
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} else {
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cp, _ := txt.Copy()
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cp.SetTargetTXTs(v)
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cp.SetLabelFromFQDN(k, domain.Name)
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domain.Records = append(domain.Records, cp)
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}
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}
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}
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}
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}
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if cache == nil {
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return errs
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}
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// check if cache is stale
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for _, e := range cache.ResolveErrors() {
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errs = append(errs, Warning{fmt.Errorf("problem resolving SPF record: %s", e)})
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}
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if len(cache.ResolveErrors()) == 0 {
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changed := cache.ChangedRecords()
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if len(changed) > 0 {
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if err := cache.Save("spfcache.updated.json"); err != nil {
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errs = append(errs, err)
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} else {
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errs = append(errs, Warning{fmt.Errorf("%d spf record lookups are out of date with cache (%s).\nWrote changes to spfcache.updated.json. Please rename and commit:\n $ mv spfcache.updated.json spfcache.json\n $ git commit -m 'Update spfcache.json' spfcache.json", len(changed), strings.Join(changed, ","))})
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}
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}
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}
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return errs
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}
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